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Light Pollution

Benefits of City Light

A systematic review of studies in the Unite States and the United Kingdom found that under improved street lighting, overall crime decreased 21.5% compared to no improvement 1.

Extent

Light pollution, characterized by the presence of unwanted light at night, is a pervasive and growing phenomenon.

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Total nighttime lights (TNL) is a measure of total light that is visible in the atmosphere of a region. See Hu and Zhang 2 for technical details on how TNL is defined. Light pollution is characterized by the presence of artificial light that is at least 8% of natural light at the darkest point, around 1 AM 3. The Milky Way becomes invisible when artificial light exceeds about 400% of natural light 3. Sources: Hu and Zhang 2 and Falch et al. 3.

Street lights receive heavy attention as a contributor to light pollution, though recent satellite observations in Tucson, Arizona found that street lights contribute 16-21% of overall light pollution 4. Other major contributors include building lighting, car lights, fishing boats, cruise ships, security lights, vehicles lamps, offshore oil platforms flares, and undersea research vessels 5.

Modern technology, and particularly computer technology, has created for many people an additional exposure to light at night.

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Source: Bedrosian and Nelson 6. Smartphone exposure is estimated at 40+ blux, which is a weighted measure of light intensity based on circadian-response frequencies.

Effects

Excess light at night has been shown to disrupt the circadian rhythm, interfering with sleep, and harm a person's mood 7. Additionally, evidence suggests that night light stimulates bodily hormone production, increasing the risk of breast and prostate cancer 8.

Light pollution has been implicated in a wide range of disruptions to ecosystems. To give a few examples, light pollution interferes with some insect behavior and may be a major factor in overall insect population declines 9; light pollution interferes with zooplankton growth and causes algae blooms 10; light from tall buildings attacts birds and contributes to bird deaths 11; and light pollution contributes to the loss of sea turtles by disrupting their travel behavior 12.

Mitigation

Street lights are a major contributor to light pollution. Over half the light produced by a typical street light is wasted.

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Source: Chepesiuk 13.

Designs of streetlights that prevent light from traveling at or above the horizontal plane greatly reduce skyglow and glare 13.

Problem:
Light Pollution
Solution:
LED Street Lights With Full Cut-Off Shielding - World
Problem:
Light Pollution
Solution:
Better Streetlight Design
Problem:
Light Pollution
Solution:
Reduce Nightime Office Building Light

Light emitting diodes (LEDs) are attractive for their long lives and energy efficiency, but LEDs, at high frequencies in particular, may perform worse than alternatives from a light pollution standpoint. For this reason, astronomers, who are particularly sensitive to light pollution, prefer low pressure sodium lights.

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Visual Pollution

Visual pollution refers to environmental sights that are regarded as aesthetically displeasing, such as billboards, litter, power lines, or mobile phone towers. According to expert judgments 15, open waste disposal pits and outdoor signage, particularly digital billboards, are the most disruptive forms of visual pollution. Billboards are associated with more frequent traffic accidents 16, while wind turbines have been found to reduce the property values of neighboring residences by 3% from visual pollution and 3-7% from noise pollution 17.

The Highway Beautification Act of 1965 limited billboards along U.S. interstates and replaced them with smaller signs displaying business logos 18. The Clean City law in São Paulo, Brazil banned outdoor advertising 19.

Visual pollution is a difficult problem to regulate because the harms associated with visual pollution, and what kinds of phemonena should be regarded as pollution, are highly subjective 20.

References

  1. Welsh, B. C., Farrington. D. P. "Effects of Improved Street Lighting on Crime". Campbell Systematic Reviews 4(1), pp. 1-51. September 2008. ↩

  2. Hu, Y., Zhang, Y. "Global Nighttime Light Change from 1992 to 2017: Brighter and More Uniform". Sustainability 12(12): 4905. June 2020. ↩ ↩2

  3. Falchi, F., Cinzano, P., Duriscoe, D., Kyba, C., Elvidge, C., Baugh, K., Portnov, B., Rybnikova, N., Furgoni, R. "The new world atlas of artificial night sky brightness". Science Advances 2(6): e1600377. June 2016. ↩ ↩2 ↩3

  4. Kyba, C. C. M., Ruby, A., Kuechly, H. U., Kinzey, B., Miller, N., Sanders, J., Barentine, J., Kleinodt, R., Espey, B. "Direct measurement of the contribution of street lighting to satellite observations of nighttime light emissions from urban areas". Lighting Research & Technology. October 2020. ↩

  5. Azman, M. I., Dalimin, M. N. Mohamed, M., Abu Baka, M. F. "A Brief Overview on Light Pollution". IOP Conference Series: Earth and Environmental Science 269, International Conference on Biodiversity, Johor Darul Takzim, Malaysia. November 2018. ↩

  6. Bedrosian, T., Nelson, R. "Timing of light exposure affects mood and brain circuits". Translational Psychiatry 7: e1017. January 2017. ↩

  7. Fonken, L. K., Sima Finy, M., Walton, J. C., Weil, Z., M., Workman, J. L., Ross, J., Nelson, R. J. "Influence of light at night on murine anxiety- and depressive-like responses". Behavioral Brain Research 205(2), pp. 349-354. December 2009. ↩

  8. Spivey, A. "LIGHT POLLUTION: Light at Night and Breast Cancer Risk Worldwide". Environmental Health Perspectives 118(12): A525. December 2010. ↩

  9. Grubisic, M., van Grunsven, R. H. A., Kyba, C. C. M., Manfrin, A., Hölker, F. "Insect declines and agroecosystems: does light pollution matter?". Annals of Applied Biology 173(2), pp. 180-189. June 2018. ↩

  10. Moore, M. V., Pierce, S. M., Walsh, H. M., Kvalvik, S. K., Lim, J. D. "Urban light pollution alters the diel vertical migration of Daphnia". Internationale Vereinigung für theoretische und angewandte Limnologie: Verhandlungen 27(2). October 2000. ↩

  11. Parkins, K. L., Elbin, S. B., Barnes, E. "Light, Glass, and Bird-Building Collisions in an Urban Park". Northeastern Naturalist 22(1), pp. 84-94. March 2015. ↩

  12. Brei, M., Pérez-Barahona, A., Strobl, E. "Environmental pollution and biodiversity: Light pollution and sea turtles in the Caribbean". Journal of Environmental Economics and Management 77, pp. 95-116. May 2016. ↩

  13. Chepesiuk, R. "Missing the Dark: Health Effects of Light Pollution". Environmental Health Perspectives 117(1): A20-A27. January 2009. ↩ ↩2

  14. Aubé, M., Roby, J., Kocifaj, M. "Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility". PLoS One 8(7): e67798. 2013. ↩

  15. Wakil K., Naeem M.A., Anjum G.A., Waheed A., Thaheem M.J., Hussnain M.Q., Nawaz R. "A hybrid tool for visual pollution Assessment in urban environments". Sustainability 11(8): 2211. April 2019. ↩

  16. Madleňák R., Hudák M. "The research of visual pollution of road infrastructure in Slovakia". In International Conference on Transport Systems Telematics, pp. 415-425. Springer, Cham. March 2016. ↩

  17. Jensen C.U., Panduro T.E., Lundhede T.H. "The vindication of Don Quixote: The impact of noise and visual pollution from wind turbines". Land economics 90(4), pp. 668-682. November 2014. ↩

  18. Federal Highway Administration. "How the Highway Beautification Act Became a Law". United States Department of Transportation. June 2017. ↩

  19. Da Silva M. "Making sense of visual pollution: The “Clean City” law in São Paulo, Brazil". In Toxic Truths, pp. 158-174, Manchester University Press. July 2020. ↩

  20. Nagle J.C. "Cell phone towers as visual pollution". Notre Dame Journal of Law, Ethics, & Pub\lic Policy 23(2): 7. January 2012. ↩